Lifespan: Unknown to 4/24 of Tenbun (1536)
Title: Governor of Harima
Lord: Uesugi Sadazane
Father: Uesugi Fusazane
Siblings: Uesugi Sadazane, Sadaaki, Sekisuiin (formal wife of Date Hisamune), Sadanori
Jōjō Sadanori served as a bushō during the Sengoku period. He was the head of the Jōjō-Uesugi family and served as the lord of Jōjō Castle in Echigo Province.
Sadanori was born as the son of Uesugi Fusazane.
Sadanori came into conflict with Uesugi Sadazane of the Nagao clan, the new military governor who toppled Uesugi Fusayoshi, the military governor of Echigo. In 1509, he also opposed Nagao Tamekage during the invasion of Echigo by Uesugi Akisada. Thereafter, he pledged his loyalty to Sadazane, the military governor. Conflict persisted with Tamekage who turned the role of the military governor into a puppet. In the ninth month of 1513, after Usami Fusatada raised arms in Ono Castle and conflict erupted between Sadazane and Tamekage, Sadanori sided with Sadazane by joining the rebellion. At the end of the tenth month, however, Sadazane was incarcerated by Tamekage and, in the first month of 1514, the forces supporting the military governor were defeated at the Battle of Ueda-no-shō Muikaichi. In the fifth month, Fusatada was forced to kill himself at Iwate Castle. The conflict ended without Sadanori himself being able to take notable actions.
For a while thereafter, a lull ensued with respect to the political situation in Echigo, but, in 1530, conflict erupted between Sadanori and Tamekage. Tamekage explained that this was caused by Ōkuma Masahide for creating a lot of interference between Sadanori and Tamekage. Tamekage, however, who was backed by the bakufu, was confronted by Sadanori and others aligned with him including the Agakita Group (kokujin, or provincial landowners, in Echigo known for their independence) and the Uesugi family. With the influence of Ashikaga Yoshiharu, the twelfth shōgun, the conflict subsided in the following year.
In the sixth month of 1531, Hosokawa Takakuni, a powerful figure in the Muromachi bakufu who backed Tamekage, was forced to take his own life in the Collapse at Daimotsu. In the ninth month of 1533, the conflict between the two reignited. On this occasion, Sadanori (Sadakane) succeeded in allying with provincial forces including the Ueda-Nagao clan and the Agakita Group as well as those from outside the province including the Aizu-Ashina and the Dewa-Sagoshi clan, heightening attacks against Tamekage. On 4/10 of Tenbun 5 (1536), at the Battle of Sanbunnoichi-ga-hara, Sadanori was routed, but, in the eighth month, he forced Tamekage into retirement. His movements thereafter are uncertain but, according to some records, there is a strong possibility that he died that same year.
In genealogical records, the names of Sadaaki and Yorifusa appear as nephews. And, in one record, Sadakane appears as Sadanori’s younger brother. Jōjō Masashige inherited the headship of the Jōjō-Uesugi clan.